A jar contains $4$ red marbles, $8$ green marbles, and $10$ blue marbles. If a marble is randomly chosen, what is the probability that it is not red?
Answer: There are $4 + 8 + 10 = 22$ marbles in the jar. There are $4$ red marbles. That means $22 - 4 = 18$ are not red. The probability is $ \frac{18}{22} = \dfrac{9}{11}$.